This highly emotive, personalized reaction we all have to smells is mostly due to the amygdala, an area of the brain responsible for processing emotions and memory. Our sense of smell benefits from a direct link to the amygdala, more so than any other sense. So a smell you encounter during an emotionally significant time becomes intertwined with your long-term memory. This is why smells can evoke such vivid past memories or feelings, without any effort.